A := $(C)
B = $(C)
C = abc
D ?= iii
D ?= 111
all:
	@echo A = $(A)
	@echo B = $(B)
	@echo D = $(D)
C += 123


test:a.o b.o c.o
	gcc -o test $^

%.o : %.c
	gcc -c -o $@ $<

clean:
	rm -rf test
	rm -rf *.o

.PHONY: clean
